Tecogen VP granted 29K restricted shares June 26

Tecogen’s VP of Business Development received a time-vested restricted stock grant, and his post-grant share ownership has been corrected to 41,389 shares.

This filing corrects an earlier one, and you can read the original Form 4 if you want to see what changed.

Rhea-AI Filing Summary

TECOGEN INC. (symbol: TGEN) is the issuer of record for a Form 4/A filing submitted to the SEC. Lafaille Stephen reported acquisition or exercise transactions in this Form 4 filing.

TECOGEN INC. (TGEN) reported that its VP of Business Development, Stephen Lafaille, received a grant of 29,013 shares of Common Stock as a restricted stock award on June 26, 2026 under the Tecogen Inc. 2022 Stock Incentive Plan. The award vests with restrictions lapsing 25% per year, and this amendment corrects his beneficially owned shares to 41,389 following the grant. No Rule 10b5-1 trading plan is reported.

Insider Trade Summary

Grant/Award: 29,013 shares

Grant/Award 1 txn

Insider Lafaille Stephen

Role VP of Business Development

Type	Security	Shares	Price	Value
Grant/Award	Common Stock F1, F2, F3	29,013	$0.00	$0.00

Holdings After Transaction: Common Stock — 41,389 shares (Direct)

Footnotes (3)

1. F1. Restricted stock award pursuant to Tecogen Inc. 2022 Stock Incentive Plan. Restrictions lapse 25% per year.
2. F2. Not applicable
3. F3. Corrected number of shares beneficially owned following restricted stock grant previously reported on Form 4 on June 30, 2026.

Key Figures

Restricted stock shares granted: 29,013 shares Transaction price per share: $0.0000 per share Shares beneficially owned after grant: 41,389 shares +1 more

4 metrics

Restricted stock shares granted 29,013 shares Grant of Common Stock to VP of Business Development on June 26, 2026

Transaction price per share $0.0000 per share Restricted stock award under Tecogen Inc. 2022 Stock Incentive Plan

Shares beneficially owned after grant 41,389 shares Total Tecogen common stock held by Stephen Lafaille following the award

Vesting rate of restricted stock 25% per year Restrictions on the restricted stock award lapse annually

Key Terms

Restricted stock award, 2022 Stock Incentive Plan, beneficially owned

3 terms

Restricted stock award financial

"Restricted stock award pursuant to Tecogen Inc. 2022 Stock Incentive Plan."

A restricted stock award is company shares given to an employee or executive that cannot be sold or fully owned until certain conditions—like staying with the company for a set time or hitting performance targets—are met. Think of it as a gift that only becomes yours after you fulfill specific obligations; for investors, these awards matter because they can increase the total shares outstanding when they vest, reveal how management is being paid and motivated, and create potential selling pressure when restrictions lift.

2022 Stock Incentive Plan financial

"Restricted stock award pursuant to Tecogen Inc. 2022 Stock Incentive Plan."

beneficially owned financial

"Corrected number of shares beneficially owned following restricted stock grant"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

FAQ

What insider transaction did TECOGEN INC. (TGEN) report in this amended Form 4?

The company reported that VP of Business Development Stephen Lafaille received a grant of 29,013 shares of Tecogen common stock as a restricted stock award on June 26, 2026 under the 2022 Stock Incentive Plan.

How many TGEN shares does Stephen Lafaille beneficially own after this restricted stock grant?

After the restricted stock grant, Stephen Lafaille beneficially owns 41,389 shares of Tecogen common stock, according to the corrected figure disclosed in this amended Form 4.

What are the vesting terms of the restricted stock award reported by TGEN?

The restricted stock award consists of 29,013 shares that vest over time, with restrictions lapsing at a rate of 25% per year, as disclosed in the award footnote.

Why did TECOGEN INC. file an amended Form 4 for this insider transaction?

The amendment was filed to correct the number of shares beneficially owned by Stephen Lafaille after the restricted stock grant. The corrected post-grant holding is 41,389 shares of common stock.

Was the TGEN insider transaction made under a Rule 10b5-1 trading plan?

No. The filing indicates that the Rule 10b5-1 checkbox is not checked, and the footnotes do not state that this restricted stock grant was made under a Rule 10b5-1 trading plan.

Did Stephen Lafaille pay any purchase price for the 29,013 TGEN shares granted?

No purchase price is associated with the grant. The filing reports a transaction price per share of $0.0000, reflecting that this was a restricted stock award rather than a market purchase.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/08/2026 - 05:12 PM Accepted by SEC EDGAR 09/08/2026 - 05:12 PM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Lafaille Stephen

(Last) (First) (Middle)

76 TREBLE COVE ROAD

(Street)

NORTH BILLERICA MASSACHUSETTS 01862

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
TECOGEN INC. [ TGEN ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	VP of Business Development

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/26/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)
06/30/2026

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock(1)	06/26/2026		A		29,013	A	$0(2)	41,389(3)	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Restricted stock award pursuant to Tecogen Inc. 2022 Stock Incentive Plan. Restrictions lapse 25% per year.

2. Not applicable

3. Corrected number of shares beneficially owned following restricted stock grant previously reported on Form 4 on June 30, 2026.

Remarks:

Filed to amend Form 4 filed by Reporting Person on June 30, 2026.

	/s/ Stephen Lafaille	09/08/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)